The present invention relates to a device for moving. a film or strip of plastics material intended particularly, but not exclusively, for recovering step by step films that are unrolled from robots for placing electronic components.
It is known that in order to assemble components quickly on a card, a robot can be used which takes a component from a dispenser film and places it at the appropriate location on a card. The thickness of the film is about 0.1 mm. The present invention relates to the film after the components have been taken from it. It is necessary to remove the film from the machine, to store it, and finally to discard it.
Traditionally, the film is wound onto the hub of a reel that is rotated. If the reel rotates at constant speed, then the winding speed of the film is irregular and depends on the extent to which the reel has been filled. As a result, the traction which is applied thereto varies, and numerous breaks are observed in such film, thereby requiring the machine to be stopped.
In order to remedy that drawback, proposals have already been made to cause the film to pass between two knurled wheels whose peripheries come into contact, and then to store the film behind the wheels in a suitable compartment. However, the film has a tendency to wind around the knurled wheels. In addition, that fixed system requires a special drive provided by means of a DC motor, and that is very expensive.
An object of the present invention is to mitigate the drawbacks of known systems and to propose a system that is simple, adjustable, and reliable.
According to the invention, the timed device for removing a strip or film, in particular a strip for carrying electronic components and after the components have been removed therefrom, comprises a clamp member driven with-reciprocating motion, synchronized by the machine, and entraining and pushing the film step by step.
In a first embodiment, the device comprises a clamp driven with synchronized reciprocating motion entraining the film into a storage cavity.
In another embodiment of the invention, the device comprises two synchronized one-way toothed wheels entraining the film step by step. The term xe2x80x9cone-way wheelxe2x80x9d is used to designate a wheel of the xe2x80x9cfreewheelxe2x80x9d, type which can rotate in one direction only.
Thus, by back-and-forth motion of a wheel, the device pushes the plastics film towards its storage location, with the applied force remaining constant over the entire length of the film so operation is safe. The pay-out step size of the strip in this type of machine lies in practice in the range 4 mm to 12 mm. This device enables the film to be advanced by a determined length synchronously with the general movement of the robot.